#include <stdio.h>
#define PI 3.1415926
int main(int argc, char *argv[]) {

    int n=0;
    scanf("%d", &n);

    for (size_t i = 0; i < n; i++)
    {
        double r = 0;
        scanf("%lf", &r);

        double area = PI * r * r;
        printf("%.6f\n", area);
    }
    

    return 0;
}